- character diagnosticus speciei naturalis, a praecipuis & peculiaribus notis, quas proles & individua neutra ejusdem fpeciei proferunt, assumi debet,ut nobis indicavit natura (Necker), the distinguishing character of a natural species, from the specific and singular distinguishing marks which neither the offspring nor an individual of the same species reproduces, ought to be assumed, as indicated by us, to be as in nature.